experiment to one of the world's most powerful companies. now, in february 2004, that mark zuckerberg and three co-founders set up the website. in less than a year, facebook had nearly 1 million users. at first, the site was restricted, just to university students in the united states. in 2005, it expanded to schools around the world. then, the following year, all of the restrictions were dropped. and facebook's explosive growth began. in 2007, it went from 12 million users to 50 million. that doubled in 2008. 2010, brought the oscar-winning movie, "the social network," that dramatized the conception. the founders weren't always happy. this is hollywood. today, facebook has more than 750 million users. it's not publicly listed yet. but current estimates put the company's valuation as high as $17 billion, andrew.